Micro Electro Mechanical System (MEMS) is an industrial technology combining the techniques of micro-electronics and mechanical engineering. Generally, the size of MEMS is within the range between micrometers (μm) and micrometers (mm). MEMS are generally manufactured using the technique of processing semiconductors, which includes silicon processing methods, such as calendering, electroplating, wet etching, dry etching and electrical discharge machining, etc.
General physical experiences are not available when the size of MEMS is under consideration. For example, since the ratio of area to volume of MEMS is much less than those of normal mechanical systems, the surface phenomenon of MEMS is much more important than the volume phenomenon of MEMS. In other words, due to the physical characteristics caused by the ratio of size, the effects caused by the noise should be considered seriously for back-end circuits of MEMS.